This invention is directed to a plasticized thermoplastic polymer composition comprising in admixture, a thermoplastic polymer selected from a polyarylate derived from a dihydric phenol and at least one aromatic dicarboxylic acid, a polyetherimide, an aromatic polycarbonate, a poly(aryl ether) having a molecular weight in excess of 10,000, and mixtures thereof, and a poly(aryl ether) having a molecular weight of from about 1000 to about 5,000.
Thermoplastic polymers such as polyarylates, polyetherimides, aromatic polycarbonates and poly(aryl ether)s are high temperature, high performance thermoplastic polymers with a good combination of thermal and mechanical properties.
However, these thermoplastics are generally processed at high temperatures. For example, polyarylates are generally processed at temperatures of about 680.degree. C. At these temperatures the mechanical properties of the polymer may be detrimentally effected. Additives have been proposed which lower the processing temperature of the polymers. However, many of these polymers are not stable at these processing temperatures. Thus, there is a desire to lower the processing temperature of the polymer without effecting the mechanical properties. Also, if an additive is used to lower the processing temperature it must be compatible with and not degrade the polymer. Further, it is also desirous that the additive improve the moldability, i.e., the ability of the molten polymer to flow in a thin-walled mold.
In the present invention it has been found that low molecular weight poly(aryl ether) improves the moldability of a thermoplastic polymer in that the ability of the thermoplastic polymer melt to flow into thin-walled molds is improved and also, the processing temperature of the thermoplastic polymer is reduced.